Waveguides are critical components for radar and communications systems. Waveguides operate by guiding the propagation of an electromagnetic wave so that the wave is forced to follow a path defined by the physical structure of the guide. Types of waveguides may be divided by the type of energy that is transmitted, including optical, microwave, and radio frequency transmissions. The present invention is concerned with the propagation of microwave energy, or energy in or near the microwave region of the electromagnetic spectrum.
Switches, couplers, splitters, filters, and other components are often used in conjunction with the waveguides to control the signal transmission.
The size of the passive filter typically dominates the volume of commercial transmitting and receiving components. Substantial miniaturization of the transmitting and/or receiving components can be achieved through the reduction in volume of microwave bandpass filters. Although conventional methods could fabricate filters during the fabrication process of transmission lines, such methods utilize large resonant structures as filters.
The U.S. patent application entitled “Waveguide Device and Method for Making Same,” (herein incorporated by reference) filed on the same day as the present application discloses a method for making high-aspect ratio waveguide by a manufacturing process known as “LIGA” (an acronym for the German: “Lithographie, Galvanoformung, and Abformung”). Thus, it is desirable to fabricate smaller filters in the waveguide when fabricating the waveguide by a LIGA process.
The manufacture of conventional RF switches is time, labor and capital intensive undertaking. It is also desirable to fabricate RF switches for the waveguide during the LIGA fabrication process of the waveguide.